I've got an 04 6.0. I replaced the FICM about a month ago due to no start and it was running great. But for the past week ive had trouble starting it. It'll crank and no start about ten times then it starts and barely runs at like 300 rpms for about 5-10 sec then goes up. It also idles all messed up. I was told possibly an ICP sensor but idk. All the diesel mechanics around here dont know anything about 6.0's expecially the dealer. The DEALER tried starting it with about half a can of ether, i was ready to kill them. I leave for college in 5 days and i NEED to fix this i dont wanna get stranded. Any help is appreciated

 

ICP sensor sounds right, if it is an early 04 they are much harder to reach, they are on the cover for the HPOP, if it a late 04 it will be right on the passenger side valve cover, see if you have an oil leak in either of those locations, alot of times with the early build people think they have a rear main seal leak but it is realy th ICP leaking, it comes right through the sensor, //
If it is an early one change it out from the top drivers side, alot easier than doing it from underneath like it is suggested, took me 2 days that way// and about an hour from the top

 

Need to get the codes pulled...

Any smoke coming out of the exhaust during cranking?

 

Thanks guys sorry I took so long to respond my computer broke. Yeah it's an early 04 so it'll be a pain. And I haven't been able to scan it yet. But I didnt notice smoke trying to start it but I wasn't really looking I'll have to check it out

 

Let us know, that will be key in which direction we point you. No smoke means the injectors are not firing at all, which is probably a pretty easy diagnosis, if you're getting smoke and it's not firing, it may be a little harder to nail down from our end, but we can at least point you to some things to check out.

 

Sounds like either a High pressure oil leak or ICP. Heres the socket to remove it. Youll need a 3 or 4 inch extension and flex head ratchet and remove the one heat sheild from the ficm to up pipe.
S6196KR, Socket, Ford ICP Sensor, 1 1/16", 3/8" square drive

 

There was no smoke turning over, but I killed the battery trying to start it. Charged it overnight went out the next morning and it started right up. So it's been starting alright alittle bit of a problem every other start bit it's still idles weird so I'm thinking ICP but idk

 

You can unplug the ICP and it will run in a safe mode/ rich/ so you can see if it makes a difference.if the computer doesn't see enough pressure it goes to a safe mode